DES MOINES, IA - OCTOBER 24: Singer Katy Perry rallies supporters of Democratic presidential candidate Hillary Clinton outside the Iowa Events Center before the start of the Jefferson-Jackson dinner on October 24, 2015 in Des Moines, Iowa. The three major candidates seeking the Democratic nomination for president are expected to attend the dinner, a major annual fundraiser for Iowa's Democratic Party. (Photo by Scott Olson/Getty Images)
